In Mac's pinking post he mentions the needle is in the lowest groove, the rich needle position. I have a 1974 850 with twin carburettors and the needles are in the highest groove. Is this correct for my 850? The Haynes Manual is not too much help it simply says to fit the needle in the same groove as when striped down!
Many thanks Roger
Raising the needle enriche…
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Don't expect to set your…
Don't expect to set your commando's amal carb by the book. They are notorious for wearing the needle jet; so expect to have to lower the needle to compensate for wear. As a general rule of thumb - if you can start it from cold without choke it is too rich and lowering needle may cure it, When you run out of grooves in the needle ( as the years roll by) either buy a new needle jet or file the partly formed groove at the top of the needle till the clip fits and get your moneys worth out of it!
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Martin, your rule of thumb…
Martin, your rule of thumb for starting without choke is reasonable but surely the pilot circuit will be doing probably 80% of the fuelling for the start. The needle and needle jet don't start working until the throttle is being opened. I know there is an overlap of each stage of the process.
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Raising the needle enrichens the mixture, ( the needle is tapered). Start with it in middle position. There are a number of Amal Parts suppliers with carb tunning advice. Try google, I found Hitchcoccs easy to follow. Good Luck.